This paper sheds light on the global migration patterns of the past 40 years, and produces migration projections for the 21st century. To do this, we build a simple model of the world economy, and we parameterize it to match the economic and socio-demographic characteristics of the world in the year 2010. We conduct backcasting and nowcasting exercises, which demonstrate that our model fits very well the past and ongoing trends in international migration, and that historical trends were mostly governed by demographic changes. Then, we describe a set of migration projections for the 21st century. In line with the backcasts, our world migration prospects are mainly governed by socio-demographic changes. Using immigration restrictions or development policies to curb these pressures requires sealing borders or triggering unprecedented economic takeoffs in migrants’ countries of origin. Increasing migration is thus a likely phenomenon for the 21st century.

本文阐明了过去40年的全球移民模式，并提出了21世纪的移民预测。为此，我们建立了一个简单的世界经济模型，并将其参数化以匹配2010年世界经济和社会人口特征。我们进行了后推和后推练习，这表明我们的模型非常适合国际移民的过去和现在的趋势，历史趋势主要由人口变化决定。然后，我们描述了21世纪的移民预测。与上述情况相吻合，我们的世界移民前景主要受社会人口变化的制约。利用移民限制或发展政策来遏制这些压力，需要密封边界或在移民的原籍国引发前所未有的经济起飞。因此，移民的增加是21世纪的一种可能现象。